The seven-day week is so deeply baked into modern life that it feels almost inevitable. Workdays, weekends, school schedules, streaming release dates — nearly everything runs on the same seven-day rhythm. But there’s nothing especially natural about a week. Unlike a year, a month, or a day, it doesn’t neatly correspond to a major astronomical event.  While a year is tied to Earth’s orbit around the sun, a month is roughly one full cycle of moon phases, and a day is one rotation of Earth on its axis, the length of a week isn’t cut and dry. So why is it seven days instead of, say, five, eight, or 12? How the Ancients Shaped the Week The seven-day week has endured for thousands of years, surviving empires, revolutions, religious shifts, and even a few determined attempts to replace it. Its origins lie in …Read More

If you were to go back in time and step into an average American kitchen in 1900, it would feel both familiar and strange. A lot of items would be instantly recognizable — the pots and pans, knives and forks, plates and bowls — but you’d soon notice the lack of certain modern tools. There would be no electric mixer, no blender, no coffee machine, and no refrigerator or freezer.  Back then, everything that happened in the kitchen was done by hand. Homemakers were expected to bake bread, preserve fruit, grind coffee, render lard, and cook hot meals on a stove that required constant attention. The luxury of pressing a single button to heat food, mill ingredients, or toast bread was nothing but a fantasy. Instead, cooks relied on a selection of manually powered devices and appliances. Here are seven such tools that …Read More

In a world without cameras, biometric databases, or even consistent spelling, identifying individuals could be quite a complex challenge. Before photography helped fix identity to an image, societies developed a range of creative methods to determine who someone was — a task that could be surprisingly difficult, especially when that someone was outside their home community. From scars to seals to signatures, here’s how identity was tracked before photo IDs. Names (and the Trouble With Them) A name was the most basic marker of identity for centuries, but it often wasn’t enough. In ancient Greece, to distinguish between people with the same first name, individuals were also identified by their father’s name. For example, an Athenian pottery shard from the fifth century BCE names Pericles as “Pericles son of Xanthippus.” In ancient Egypt, the naming convention might have reflected the name of a …Read More

Even if you’ve never been hauled downtown in a paddy wagon, there’s a chance you’ve had your fingerprints taken. They’ve been used to establish people’s identities for thousands of years, but it wasn’t until the early 20th century that police used them to track criminals.  Before that, the Bertillon system was the standard identification method in much of Europe and the U.S. It measured more than a dozen different body parts — including the ears, nose, arms, head circumference, sitting height, and standing height — to identify suspects and criminals. Eye color, scars, and other distinguishing features were noted on a standardized card that also included a mug shot. The system was named for its creator, French anthropologist Alphonse Bertillon, who developed it in 1879. By 1898, 10 American cities including New York, Philadelphia, and Boston had begun using the system and coordinating …Read More

For drivers in many parts of the globe, the red, yellow, and green sequence of traffic lights has become an instinctual part of how we move through the world. But why these three colors? How did they come to govern the movement of billions of people across the planet every day? As it turns out, there are a few factors in play, including the history of transport, color psychology, and basic physics.  Red Lights and Railroads The colors used in traffic lights today were not invented for roads. They were largely inherited from the railway industry, which began developing light-based signaling systems in the 1830s (based on even older semaphore flagging). But in the early days of railroads, the colors were slightly different: While red was used to signal “stop,” white meant “go,” and green was the color used to indicate caution. The …Read More

The famed general is remembered for his iconic bicorn hat, his allegedly short stature, and his singular military skill.